Process of obtaining aromatic hydrocarbons.



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FLETCHER B. HOLMES, OF WOOIDBURY, NEW JERSEY, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 E. I. DU PONT DE NEMOUBS AND COMBANY, A CORPORATION OF DELAWARE.

PROCESS OF OBTAINING AROMATIC I-IYDBOCARBONS.

No Drawing.

To all whom it may concern:

Be it known that I, FLETCHER B. HOLMES, of Woodbury, in the county of Gloucester and in the State of New Jersey, have invented a certain new and useful Improvement in Processes of Obtaining Aromatic Hydrocarbons, and do hereby declare that the following is a full, clear, and exact description thereof.

My invention relates to a process for obtaining aromatic hydrocarbons from a solution or mixture of such hydrocarbons with other products, as for example, petroleum products. More particularly, however, it relates to a process in which gasolene containing varying percentages of aromatic hydrocarbons is separated so as to obtain one product having a much larger percentage of aromatic hydrocarbons than the original gasolene, and another product containing a much smaller percentage of such hydrocarbons than in the original gasolene.

Petroleum obtained from certain sources contains appreciable percentages of aromatic hydrocarbons, and such aromatic hydrocarbons are present in the fraction thereof known as gasolene obtained by distillation. Such aromatic hydrocarbons are also present in the gasolene obtained from petroleum products by special means, asby treatment at higher temperatures and pressures. It is well known, however, that it is diflicult to concentrate a diluted solution of the aromatic hydrocarbons and gasolene by fractional distillation, as the aromatic hydrocarbons begin to distil at temperatures far below their actual boiling points, and furthermore, continue to distil together with the gasolene at temperatures far above their boiling points.

The object of my invention is to provide a practical and an effective method of sepa rating the aromatic hydrocarbons from such petroleum products, thus avoiding the di'liiculties found in the separation as pointed out above.

I have discovered that if the petroleum products containing percentages of aromatic hydrocarbons are treated with a solvent, as for example a non-volatile solvent, having a different solvent action upon the aromatic hydrocarbons than upon the paraflin hydrocarbons contained in the products, a separation of the aromatic hydrocarbons from the Specification of Letters Patent. Patented Aug. 20, 1918. Application filed April 27, 1915. Serial N 0. 24,330. i i

covered that this separation can be very etiec-I tively carried out by the use of a nitro-compound, or a mixture 'of nltro-compounds,

especially substances consisting substantially of nitro-bodies of a higher. degree of nitration than the mono-nitro-compounds. While my invention is capable of being carried out in many different ways, for the purpose of illustration I shall describe only one Way in which ried out. I p

I may proceed as follows: Gasolene containing a small percentage of aromatic hydrocarbons is mixed in any suitable manner with an equal weight of the nitro-compound product known as liquid di-nitrotoluol.'

This mixture is then allowed to stand until it separates into two layers. The lower layer is comprised mainly of liquid di-nitrotoluol together with a quantity of. gasolene and aromatic hydrocarbons. The upper layer is comprised mainly of gasolene with small percentages of aromatic hydrocarbons t0- geth'er with a small amount of liquid dinitrotoluol. The two layers are then separated and separately distilled so as to separate the nitro-compound from the gasolene and hydrocarbons. Preferably the distillation is carried out at a reduced pressure, or by the injection of a current of steam or inert gas through the liquid, as the separation from the nitro-compound may be more readily effected in this manner. A distillate will thus be recovered from the lower layer having the higher percentage of aromatic hydrocarbons, While the distillate obtained from the upper layer will contain a. lower percentage of the aromatic hydrocarbons.

Each of the distillates may then be treated my invention may be carcarbons. It will be understood, of course,.

that'the nitro-compound may be repeatedly used in the manner above described.

While I have described my process above as being-carried out by the application of liquid di-nitrotoluol as a solvent suitable for the separation of the constituents in the" petroleum products, other nitro-compounds and nitro-compound mixtures can be used equally well. It.is also to be understood that the process may be modified, if desired, in such a way as to carry it on continuously; It is also to be understood that where I have referred to a non-volatile solvent, I mean a solvent having a boiling point higher than 150 degrees centigr'ade. Solvents having a high boiling point may be much more readily separated from gasolene or aromati hydrocarbons.

While I have described my invention above in detail, I wish it to be understood that many changes may be made therein without departing from the spirit of my in vention.

Furthermore, in the claims I have referred to an aromatic nitrocompound, but I mean to include thereby either'a single such compound or a mixture of such compounds.

I claim:

1. .The process which comprises treating a petroleum product containing aromatic hydrocarbons with an aromatlc nitro-comound of such a nature as Wlll separate the "petroleum product into a part containing a higher percentage and a part containing a low percentage of aromatic hydrocarbons than in the said petroleum product.

2. The process Which comprises treating a petroleum product containing aromatic hydrocarbons with an aromatic nitro-c'ompound of a higher degree of nitration than the mono-nitro-compound of such a nature as will separate the petroleum product into a part containing a higher percentage and a part containing a lower percentage of mo matic hydrocarbons than 1n the said petroleum product.

3. The process which comprises treating a petroleum product contalnlng aromatic hydrocarbons with a. liquid aromatic nitrocompound so as to separate the petroleum product into a part containing a higher per .centage and a part containing a lower'perdrocarb-onsthan in the said etroleum product.

5. The process which comprises treating a gasolene containlng aromatic hydrocarbons with an aromatic nitro-compound or" such a nature as will separate the gasolene.

into a part containing a higher percentage and a part containing a lower percentage of aromatic hydrocarbons than in the said gasolene.

6. The process which comprises treating a gasolene containing aromatic hydrocarbons with an aromatic nitro-compound of a higher degree of nitration than the monov nitro-compound of such a nature as will separate the gasolene into a part containing a higher percentage and a part containing a lower percentage of aromatic hydrocarbons than in the said gasolene.

7. The process which comprises treating a gasolene containing aromatic hydrocarbons with a liquid aromatic nitro-compound so as to separate the gasolene into a part conta1n-' ing a higher percentage and a part containing a lower percentage of aromatic hydrocarbons than in the said gasolene.

8. The process which comprises treating a gasolene containing aromatic hydrocarbons with a liquid aromatic nitro-compound of a higher degree of nitration than the mononitro-compound so as to separate the gasolene into a part, containing a higher percentage and a part containing a lower percentage of aromatic hydrocarbons than in the said gasolene.

'In testimony that I claim the foregoing I have hereunto set my hand.

FLETCHER B. HOLMES.

I Witnesses:

A. M. CoMEY, W. R. MOWBRAY, Jr. 

